package/libvirt: libvirtd needs C++ for nmap-ncat

Fix the following build failure raised since commit
fbf25acfbfd5a73b3560918bea081768abbe5723:

WARNING: unmet direct dependencies detected for BR2_PACKAGE_NMAP
  Depends on [n]: BR2_INSTALL_LIBSTDCPP [=n] && BR2_USE_MMU [=y] && BR2_TOOLCHAIN_HAS_THREADS [=y]
  Selected by [y]:
  - BR2_PACKAGE_LIBVIRT_DAEMON [=y] && BR2_PACKAGE_LIBVIRT [=y] && !BR2_PACKAGE_NETCAT_OPENBSD [=n]

Fixes:
 - No autobuilder failures (yet)

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
[yann.morin.1998@free.fr: C++ only needed without NETCAT_OPENBSD]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/libvirt/Config.in

@@ -44,6 +44,7 @@ if BR2_PACKAGE_LIBVIRT
 config BR2_PACKAGE_LIBVIRT_DAEMON
 	bool "libvirtd"
 	default y
+	depends on BR2_INSTALL_LIBSTDCPP || BR2_PACKAGE_NETCAT_OPENBSD # nmap
 	select BR2_PACKAGE_BUSYBOX_SHOW_OTHERS
 	select BR2_PACKAGE_DNSMASQ
 	select BR2_PACKAGE_EBTABLES
@@ -57,6 +58,9 @@ config BR2_PACKAGE_LIBVIRT_DAEMON
 	  Build the libvirt daemon (libvirtd) otherwise build only the
 	  utility programs.
 
+comment "libvirtd needs a toolchain w/ C++"
+	depends on !BR2_INSTALL_LIBSTDCPP && !BR2_PACKAGE_NETCAT_OPENBSD
+
 # Stateful drivers are useful only when building the daemon.
 if BR2_PACKAGE_LIBVIRT_DAEMON